New York Times (July 4, 2011): In Southern 'Stroke Belt,' Erosion of Memory Is More Likely Too

People in a large area of the American South have long been known to have more strokes and to be more likely to die from them than people living elsewhere in the country.

Now, a large national study suggests the so-called stroke belt may have another troubling health distinction. Researchers have found that Southerners there also are more likely to experience a decline in cognitive ability over several years - specifically, problems with memory and orientation.

The differences to date in the continuing study are not large: Of nearly 24,000 participants, 1,090 in eight stroke-belt states showed signs of cognitive decline after four years, compared with 847 people in 40 other states.

But the geographic difference persisted even after the researchers adjusted for factors - like age, sex, race and education - that might influence the result. The most recent data from the study were published in Annals of Neurology.

None of the people with cognitive decline in the study had had detectable strokes. But some experts believe their memory problems and other mental issues could be related to the same underlying risk factors, including lifestyle patterns that contribute to hypertension, high cholesterol, diabetes and obesity.

Is it the fried food beloved by Southerners? Limited access to doctors? Too little exercise? Researchers are investigating those and other possible causes. Some experts also suggest that the participants could have had small, undetectable strokes that subtly affected brain function.

“This should be a very strong alarm signal,” said Dr. Gustavo C. Roman, who leads the neuroepidemiology section of the American Academy of Neurology and was not involved in the study. The finding suggests that “if you want to keep your marbles, you need to control your blood pressure, excessive weight and other risk factors for stroke.”